immune system Flashcards
What is a monoclonal antibody
an antibody produced by a single clone of cells
outline the process of phagocytosis
pathogen engulfed and put into phagosome
lysosomes fuse with phagosome
lysosomes release lysozymes that hydrolyse pathogen
products absorbed by phagocyte
what is an antigen
a molecule that triggers an immune response
by lymphocytes
where in the body do B-lympocytes mature
In the bone marrow
Describe how B-lymphocytes respond when they are stimulated by antigens.
they divide by mitosis and produce plasma cells which make antibodies and memory cells
what is vaccination
the injection of dead or attenuated pathogens or antigen preperation that stimulate the formation of memory cells
what do helper t cells do
release cytokines that activate and stimulate phagocytes cytotoxic t cells and B-cells
what are B lymphoyctes
they are a type of white blood cell that produce antibodies
outline the process of clonal selection
when the antibody on a B-cell surface meets a complementary shaped antigen it binds to it.
this along with the substances from the helper t cell
what does clonal selection cause B cells to undergo
divide by mitsosis to form plasma cells
what are plasma cells
cells that are identical to B cells
they secrete loads of antibodies specific to the antigen
they bind to the antigens on the surface of the pathogen
form lots antigen-antibody complexes
why does an antibody have two binding sites
so it can bind to two pathogens at once
this means pathogens are clumped together
this is called agglutination
what do phagocytes to do pathogens with antibodies binded to them
they carry out phagocytosis on them and destroy them
what are the two types of immune response
cellular and humoral response
what is the role of cytotoxic t cells
they kill foreign cells and abnormal body cells
what is the cellular response
The T cells and other immune cells that they interact with. form the cellular response
what is the humoral response
B cells,clonal selection and the production of monoclonal antibodies form the humoral response
name two ways pathogens cause disesase
releasing toxins
damaging cells/tissues
how can monoclonal antibodies be used with anti-cancer drugs
cancer cells have antigens called tumour markers
monoclonal antibodies made specific to tumour markers
drugs only accumulate in bodies with cancer cells
antibody binds to markers with cancer drug attached
how can monoclonal antibodies be used in pregnancy tests
application area antibodies complimentary to hgc protein.
urine applied hgc will bind to antibody on beads
urine moves up stick to test strip where hgc antibodies are
if hgc present it will go blue if it is not the beads pass through
outline the direct elisa test
antigens from sample bound to well plate
detection antibody with enzyme complimentary to antigen added
if antigen is present it will be immobilised
well is washed to remove unbound antibody
substrate solution added if antibody present colour change occurs as enzyme reacts with substrate
outline indirect elisa test(HIV test)
antigen bound to bottom of well plate
sample of blood is added if specific antibody present will bind to antigen
well washed out to remove unbound antibody
secondary antibody with enzyme added which can bind to antibodies well washed out again
solution added is antibody is present colour change will occur
outline the t-lymphocyte response
antigen presenting cell
receptors on specific helper t cells complimentary to antigens on antigen presenting cell
attachment activates t cell to divide rapidly by mitosis and form a clone of genetically identical cells
cloned t cells either
develop into memory cells
or
stimulate the other cells into immune response and active killer t cells
What is active immunity
Immunity that requires memory cells to be made
Can be obtained by vaccines, suffering disease once
It is long lasting
What is passive immunity
Immunity that is obtained by an injection/giving of antibodies.
What is natural passive immunity
Through the placenta or breast milk
What is artificial passive immunity
Via injection
Why may vaccination not eliminate disease
It fails to induce immunity in certain people
People develop disease immediately after vaccination
Pathogen may mutate frequently so antigens change frequently
What is herd immunity?
Where unvaccinated people are protected because of the occurrence of the disease is reduced by the number of people who are vaccinated
what does HIV do in the body
It infects and kill helper t cells
Without enough helper t cells immine system unable to mount an effective response
Immune cells don’t behave how they should
